This invention relates to air cooling equipment for use in electronic systems such as communications systems and information processing systems.
In general, active elements such as transistors mounted on a printed circuit wiring board tend to generate heat proportional to the dissipated electric power. The heat produced has an adverse effect on characteristics of the active elements and, if too great, can result ultimately in the destruction of those active elements. For this reason, a strict environmental temperature restriction is imposed on these electronic components to ensure reliability. This temperature restriction is easily met in circuits using only a few active heat producing elements. However, recently, electronic systems need to concentrate a great number of active elements on a chip in a high density arrangement to achieve high speed operation and microminiaturization. Accordingly, an increase in the number of active elements is accompanied with the attendant increase of the electric power dissipation and the quantity of heat produced which must be dissipated. This is typically accomplished by means of cooling equipment for effectively cooling the electronic components to maintain the temperature of the electronic components below their maximum operating temperature.
One attempt for the practical use of such cooling equipment is disclosed in an air cooling system in U.S. Pat. No. 4,158,875. In the system described in that patent, a plurality of blowers are arranged with the edges of a plurality of wiring boards adjacent each other. Thus, the distance between elements connected to each other becomes longer. As a result, a high speed operation in such electric systems cannot be achieved. Furthermore, in order to obtain the air flow rate required to fully cool the electronic components, a bulky air blower is needed resulting in requiring a large area dedicated to intake and exhaust ducts. Accordingly, it is difficult operation to exchange the components for maintenance.